What is the use of the shell-opening and pearl-retrieving skills in The Deer and the Cauldron?

That thing has a chance of coming out when you fight bandits. You can buy it at a stall for about 3~5~~The skill is to get Feng Shui Lingzhu particles (making Fengshui Lingzhu) in the wild forbidden area of ​​​​Longju. The skill is useless~ There is only one shell in the forbidden area~~Don’t spend 30j to buy it~Go and fight the bandits~~